Mongo shell 是 MongoDB 的命令行管理工具，功能非常强大，最近社区很多人咨询的一些问题，比如
- 命令行看 json 格式比较吃力？
- 如何确定Secondary节点同步是否跟上？
- 怎么查看DB、集合使用了多少空间？
- 能否在shell 脚本里调用Mongo shell
- 怎么执行 MongoDB 命令，比如创建集合、索引？
- ……
上述问题都可以通过 Mongo shell 来解决，而且Mongo shell能做的远不止这些。
语法糖
为了方便关系型数据库的的用户切换到 MongoDB 上能快速上手，mongo shell里做了一些语法上的兼容（最终还是通过调用 MongoDB 的命令实现的 ），例如
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<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> dbs 列出所有DB <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>use</span> dbname 切换当前DB <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>tables</span> 或 <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> collections 列出当前DB的所有表/集合 <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>users</span> 列出当前DB的所有用户 <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> profile 列出当前DB的所有慢查询 <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>show</span> <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>logs</span> 列出运行日志
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执行命令
MongoDB的所有请求都以命令的形式发出，支持的命令列表参考Database Commands
基本所有的driver都会实现一个通用的执行命令的接口，然后再封装出一些常用的接口（比如常用的CRUD操作），mongo shell 通过 runCommand 接口来实现执行命令，例如执行 serverStatus 命令
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* <span class=“hljs-selector-tag” style=“box-sizing: border-box;”>db</span><span class=“hljs-selector-class” style=“box-sizing: border-box;”>.runCommand</span>( { <span class=“hljs-attribute” style=“box-sizing: border-box; color: rgb(102, 217, 239);”>serverStatus</span>: <span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>1</span>} )
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mongo shell也对很对很多常用的命令进行了封装，让用户使用起来更简单。
常见的封装接口包括
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<span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.serverStatus() 查看mongod运行状态信息 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.stats() 查看db元数据 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.collection.stats() 查看集合元数据 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.collection.insert() / update / remove / find 对集合增删改查 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.collection.createIndex() 创建索引 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.collection.dropIndex() 删除索引 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.dropDatabase() 删除DB <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.printReplicationInfo() <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>db.printSlaveReplicationInfo() 查看复制集同步信息 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>rs.status() 查看复制集当前状态 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>rs.conf() 查看复制集配置 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>rs.initiate() 初始化复制集 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>rs.reconfig() 重新配置复制集 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>rs.add() / rs.remove() 增加/删除复制集节点 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>sh.enableSharding() 对DB启用分片 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>sh.shardCollection() 对集合进行分片 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>sh.status() 查看sharding状态信息 <span class=“hljs-bullet” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>* </span>...
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文档格式化输出
很多同学在使用 mongo shell时，觉得文档输出后可读性差，比如
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mongo–<span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>9555</span>:PRIMARY> db<span class=“hljs-selector-class” style=“box-sizing: border-box;”>.collection1</span><span class=“hljs-selector-class” style=“box-sizing: border-box;”>.find</span>() <span class=“hljs-comment” style=“box-sizing: border-box; color: rgb(117, 113, 94);”>// 对集合调用find时，默认输出前20个文档 { "_id" : ObjectId("587ed6ce098a4da78d508468"), "name" : "jack", "age" : 18, "sex" : "male", "hobbies" : [ "football", "basketball" ], "contact" : { "phone" : "10000123456", "address" : "hangzhou", "zipcode" : "31000" } }
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实际上，mongo shell 可以对cursor的输出进行格式化(pretty)输出，JSON的文档会被格式化输出，可读性很强
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mongo–<span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>9555</span>:PRIMARY> db<span class=“hljs-selector-class” style=“box-sizing: border-box;”>.collection1</span><span class=“hljs-selector-class” style=“box-sizing: border-box;”>.find</span>().pretty() { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"_id"</span> : ObjectId(<span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"587ed6ce098a4da78d508468"</span>), <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"name"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"jack"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"age"</span> : <span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>18</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"sex"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"male"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hobbies"</span> : [ <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"football"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"basketball"</span> ], <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"contact"</span> : { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"phone"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"10000123456"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"address"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hangzhou"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"zipcode"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"31000"</span> } }
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mongo shell 里还可以通过 printjson 来格式化输出任意json对象，比如
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mongo–<span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>9555</span>:PRIMARY> printjson({ <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"_id"</span> : ObjectId(<span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"587ed6ce098a4da78d508468"</span>), <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"name"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"jack"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"age"</span> : <span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>18</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"sex"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"male"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hobbies"</span> : [ <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"football"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"basketball"</span> ], <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"contact"</span> : { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"phone"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"10000123456"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"address"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hangzhou"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"zipcode"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"310000000"</span> } }) { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"_id"</span> : ObjectId(<span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"587ed6ce098a4da78d508468"</span>), <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"name"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"jack"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"age"</span> : <span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>18</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"sex"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"male"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hobbies"</span> : [ <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"football"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"basketball"</span> ], <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"contact"</span> : { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"phone"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"10000123456"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"address"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"hangzhou"</span>, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"zipcode"</span> : <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"31000"</span> }
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shell脚本调用
mongo shell 除了支持交互式的调用方式，还能支持执行完一个或一批操作后自动退出，这样就能很方便的在shell 脚本里调用 mongo shell，比如获取 MongoDB 各个命令备调用的次数。
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$ mongo <span class=“hljs-comment” style=“box-sizing: border-box; color: rgb(117, 113, 94);”>—host localhost:27017 —eval "printjson( db.serverStatus().opcounters )"</span> MongoDB shell version: <span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>3.0</span>.<span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>5</span> connecting to: localhost:<span class=“hljs-number” style=“box-sizing: border-box; color: rgb(174, 129, 255);”>27017</span>/test { <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"insert"</span> : 2, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"query"</span> : 13, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"update"</span> : 0, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"delete"</span> : 0, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"getmore"</span> : 74191, <span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"command"</span> : 104198 }
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如果要一次执行很多个 MongoDB 的操作，可以将操作写到文件里，然后使用 mongo shell 批量执行
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<span class=“hljs-variable” style=“box-sizing: border-box;”>$cat</span> <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>test</span>.js <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>db</span> = <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>db</span>.getSiblingDB(<span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"mydb"</span>) <span class=“hljs-comment” style=“box-sizing: border-box; color: rgb(117, 113, 94);”>// 脚本里切换db的方式，相当于use mydb for (var i = 0; i < 100; i++) { db.collection.insert( {x: i} ) } printjson( {db.collection.count()} ) $ mongo –host localhost:27017 test.js MongoDB shell version: 3.0.5 connecting to: localhost:27017/test 100
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mongo shell 还提供『启动时执行脚本』的机制，类似与linux shell里的启动新的shell时，执行~/.bashrc等文件的机制。
只要将脚本写入 ~/.mongorc.js 文件里， mongo shell 启动时，就会先执行这个脚本，例如
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<span class=“hljs-variable” style=“box-sizing: border-box;”>$cat</span> .mongorc.js <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>print</span>(<span class=“hljs-string” style=“box-sizing: border-box; color: rgb(230, 219, 116);”>"Welcome, ZhangYoudong"</span>); 然后每次登录mongo <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>shell</span>时，这个文件的js脚本就会被执行 $ mongo —host localhost:27017 MongoDB <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>shell</span> <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>version</span>: 3.0.5 connecting to: localhost:27017/<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>test</span> Welcome, ZhangYoudong >
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man 手册
上述的命令，并不需要去记忆，跟使用 linux shell 一样，需要用的时候看下 help 信息
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* <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span> * db.<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span>() * rs.<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span>() * <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>sh</span>.<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span>() * db.collection.<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>find</span>().<span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span>() * <span class=“hljs-keyword” style=“box-sizing: border-box; color: rgb(249, 38, 114);”>help</span> misc
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除了上述功能，mongo shell 还提供了命令补全、命令历史等很多实用的功能，只要习惯了使用mongo shell，根本无需再使用图形界面来管理 MongoDB；当然为了方便更多用户，阿里云 MongoDB 云数据库 不仅支持通过mongo shell 及 其他第三方图形管理工具访问，还附带一个DMS的数据库管理系统，供用户免费使用。
未经允许不得转载：主机百科 » Mongo shell使用方法及操作指南
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